1. Field of the Invention
The present invention relates to operation of rheometric instruments, and more particularly, to graphical and programming interface systems and methods for dynamically controlling operation of rheometric instruments.
2. Background Information
The term “rheology” relates to the study of the deformation and flow of matter. Rheological testing was originally associated with the examination of properties and behavior of materials such as asphalt, lubricants, paints, plastics, rubber, and fluids. Such materials may exhibit rheological properties that are not easily described through classical fluid mechanics and elasticity. Developers of other products, including many that are associated with general consumer use, are also studying the rheological aspects and profiles of their respective products, because the changes to a product's consistency in response to applied conditions (e.g., vibration or stress) may affect its performance. Such products include plastics (bottles, films), food condiments (e.g., chocolate, mustard, ketchup, or salad dressings), cosmetics (e.g., nail polish, hair products, creams and lotions), and toiletries (e.g., toothpaste, deodorants).
Rheological instruments, or “rheometers” (also referred to as viscosimeters or viscometers), can be used to measure intrinsic material characteristics relating to, for example, a substance's viscosity or modulus. Viscosity is an internal property of a fluid that offers resistance to flow (i.e., it concerns the thickness of a liquid). Rheological measurements can be performed by, for example, placing a sample between parallel plates, and performing a variety of tests, such as controlled stress tests, controlled strain tests, dynamic mechanical tests, etc.
Known rheometers are typically designed to enable a user to perform a test selected from a discrete number of different available test procedures that are implemented in the instrument firmware, and executed by a dedicated CPU in the instrument hardware. A user operates the instrument by means of a graphical user interface program typically hosted on a PC connected to the rheometer via a serial port or network connection. Once a type of test is selected, the user interface may provide a form or template, and the user is instructed to enter a set of parameters and possibly certain options that are associated with the test to complete the form. Some rheometers enable users to configure the instrument to perform a sequence these tests, allowing uses to separately configure the parameters in each test.
For example, a user of a rheometer or other operator may be interested in testing the viscosity of asphalt using a frequency sweep test. A sinusoidal strain signal is applied to the asphalt at a fixed amplitude and range of frequencies selected by the user, and the resulting stress signal is measured, with data points reported at each frequency to determine trends in viscosity as the frequency is changed. For other measurements, for example, an amplitude sweep and a temperature sweep can be performed.
Modern rheometers are pre-configured, or pre-programmed, to perform types of tests that are typically performed on certain substances. For example, known instruments are configured to perform between ten and thirty different types of pre-programmed tests, where parameters for each test procedure are adjustable according to different frequency, amplitude, temperature, etc. profiles. Like most electronic devices, an advantage associated with operating a pre-programmed system is that any of the available tests can be easily configured in a simple-to-use graphical user interface. In this manner, a rheologist need not consult with a computer programmer in connection with frequently-performed tests and experiments.
As the field of rheology continues to evolve, it is becoming more common for scientists to customize testing of materials in a manner that was not anticipated by instrument manufacturers. For example, it would be unlikely that conventional rheometers are pre-configured to run a temperature ramp concurrently with frequency sweeps. In conventional rheometer systems in which the testing procedure is completely integrated with the instrument, it might not be possible to alter the instrument programming to achieve this level of customization without modifications to the instrument firmware and the controlling software. If the controller for the interface is PC-based, then the instrument owner may be able to retrofit the software to perform the specialized test, but only after significant computer programming is performed. Such alterations to the user interface may detract from performing other tests using the instrument, and the information required to make these modifications is generally not available to the end user. Accordingly, the pre-configurability of conventional rheometer instruments is disadvantageous in situations where a scientist wishes to design a customized testing pattern.
In view of the foregoing, it can be appreciated that a substantial need exists for a method and system for performing more flexible and customized testing of a sample on a rheometer. An improved interface is thus desired that is easy-to-use, but provides additional functionality for enabling users to design and execute customized testing in addition to more commonly-performed testing.